A vehicle's suspension is a component of the vehicle most susceptible to damage and it is often overlooked. The issue of spring sag in motor vehicles is a common aspect, often arising as manufacturers opt to go for comfort rather attain carrying ability. The consumer being unaware, expects the vehicle to carry full payload upon demand. However, this often is not possible with present day vehicles on the market as they generally all follow the same industry standard and have not addressed the carrying problem. The prior art has failed to provide a soft and comfortable ride as well as the correct carrying ability thereby creating maximum sag under full load.
There are serious issues for owners who are aware of the vehicle's carrying capacity but cannot achieve it because the springs are unable to constantly carry the load stipulated by the manufacturers. Therefore spring damage can be caused by the owner believing the vehicle is capable of carrying the full pay load placed upon it.
Spring damage is a serious issue but not the primary problem. It is the carrying ability and overall wear and tear that causes serious safety issues with the vehicle and the driver. In particular, steering and braking is seriously compromised by a soft and sagging suspension.
During the carrying of such a load, the vehicle becomes unsafe and unroadworthy as spring sagging reduces the traction to front wheels and stability control of the vehicle and reduces braking performance.
When the vehicle is carrying a heavy load, the vehicle is so weighed down to possibly cause the load to rock and sway. The wheels of the vehicle most likely will also often hard bounce off the road surface upon hitting bumps. A good suspension with an undamaged leaf spring assembly will improve performance by stabilizing the rear suspension to retain control with the wheels on the ground.
The prior art generally fails in providing a method of reducing or eliminating sagging and ensuring that the vehicle is safe to handle when carrying a heavy load by stabilizing body roll and improving braking performance.
In addition, the prior art fails in providing a method of reducing or eliminating rear spring sagging caused by the attachment of the vehicle to a trailer.
A common though low effectiveness technique provided by the prior art is to have the springs reset with an extra leaf. This requires removing the spring leaf assembly from the vehicle and is an expensive, timely and labour intensive process. In addition, the result of this technique causes an uncomfortable ride when no load is carried by the vehicle and inevitably, sagging will occur generally within 12 to 24 months if continuous maximum load is carried.
Currently the prior art has provided a leaf spring system as disclosed in AU 200158004. This is not commonly or generally known disclosure, however, such prior art documents have resulted in a number of significant disadvantages described herein. The tensioning of u-bolts at the rear of the leaf spring system in this patent application are unable to sustain continuous weight and movement in the forward and backward motion as the major spring pack flexes and the length of the spring is increased and decreased. Therefore the u-bolts are prone to snapping and breaking.
The nature of the invention in AU 200158004 comprises of a bulky and wide plate that protrudes above the spring and often interferes with LPG and petrol tanks, and also exhausts by rubbing or knocking continuously during a ride. This patent application provides for u-bolts to assist in the attachment to a leaf spring assembly. However, in the patent application, the inverted u-bolt further limits the distance between the load helper and the chassis rail and can therefore damage the chassis if the vehicle, for example, goes over a bump. In addition, the u-bolt can be over tightened and cause spring breakage.
One of the major problems in the prior art is the spring slippage or dislodgement of the spring which occurs as the leaf spring assembly is trying to move with the u-bolt as it is not designed to move independently in the backwards and forwards direction.
Therefore, the prior art lacks the ability to provide a suspension system with leaf spring assemblies to improve ride quality, load carrying capacity, towing and handling improvements, all of which add up to safer, more comfortable and enjoyable driving experience and achieve minimum sag to the rear of the vehicle.
Accordingly, it is an object of the present invention to at least partly overcome or ameliorate at least one of the disadvantages of the prior art or at least provide a viable alternative.